Pen



FIG. 1 is a front elevational view showing my design;

FIG. 2 is a left side view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a top view of the cap of the pen shown in FIG. 1 with the pen removed and not shown for convenience.

FIG. 6 is a bottom view thereof; and,

FIG. 7 is a front elevational view of the pen shown in FIG. 1 with the cap removed and not shown for convenience.

The broken lines showing portions of FIG. 4 are included to show features that form no part of the claimed design. 

CLAIM The ornamental design for a pen, as shown and described. 